scholarly journals Wavelength Characteristic Analysis of a FBG Array Embedded in Quaternary Unconsolidated Strata during a Deep Borehole Installation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Dingding Zhang ◽  
Chenyang Ma ◽  
Yanyan Duan ◽  
Wengang Du ◽  
Jinxuan Liu ◽  
...  
Keyword(s):  
Real Time ◽  
Wavelength Division Multiplexing ◽  
Wavelength Shift ◽  
Deep Borehole ◽  
Field Scale ◽  
Real Time Monitoring ◽  
Transmission Characteristics ◽  
Characteristic Analysis ◽  
Wavelength Division ◽  
Sensing System

Real-time monitoring of settlement and deformation within a coal mine’s deep quaternary unconsolidated strata presents challenges with installation and signal analysis. This paper presents results from successfully installing a field-scale fiber Bragg grating (FBG) sensing system in a deep borehole for the purpose of achieving real-time monitoring of the settlement and deformation in a deep unconsolidated stratum. A 152 m deep by 133 mm diameter borehole was used to embed an array of 24 FBG sensors in 12 layers of gravel and clay from between 92.4 m and 148.7 m of unconsolidated quaternary strata. A wavelength bandwidth of ±4.5 nm was used with a wavelength division multiplexing and spatial division multiplexing technique to compose a 4-by-6 sensor array. During the four stages of installation, the real-time transmission characteristics and the changes in the FBG wavelength for this sensing system were evaluated. While the FBG sensing system was stable after installation, it was clearly shown that the engineering techniques associated with both positioning and grouting influenced the mechanical properties and transmission characteristics of the system. After installation, the sensor survival rate was found to be 78.26% with a maximum FBG wavelength shift of 1.447 nm. This field-scale installation has provided information and experience that will improve future installations of buried fiber optic sensing technology throughout the underground coal mine industry.

scholarly journals Opto-Mechatronics System for Train-Track Micro Deformation Sensing

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 296
Author(s):  
Weibing Gan ◽  
Shiyu Tu ◽  
Yuan Tao ◽  
Lingyun Ai ◽  
Cui Zhang ◽  
...  
Keyword(s):  
Wavelength Division Multiplexing ◽  
Large Scale ◽  
Time Domain Reflectometry ◽  
Wavelength Shift ◽  
Train Track ◽  
Long Distance ◽  
Wavelength Division ◽  
Track System ◽  
Signal Demodulation ◽  
Micro Deformation

In this paper, we proposed and experimentally demonstrated an opto-mechatronics system to detect the micro-deformation of tracks caused by running trains. The fiber Bragg grating (FBG) array acting as sensing elements has a low peak reflectivity of around −40 dB. The center wavelengths were designed to alternate between 1551 nm and 1553 nm at 25 °C. Based on dual-wavelength, wavelength-division multiplexing (WDM)/time-division multiplexing (TDM) hybrid networking, we adopted optical time-domain reflectometry (OTDR) technology and a wavelength-scanning interrogation method to achieve FBG array signal demodulation. The field experimental results showed that the average wavelength shift of the FBG array caused by the passage of the lightest rail vehicle was −225 pm. Characteristics of the train-track system, such as track occupancy, train length, number of wheels, train speed, direction, and loading can be accurately obtained in real time. This opto-mechatronics system can meet the requirements of 600 mm spatial resolution, long distance, and large capacity for monitoring the train-track system. This method exhibits great potential for applications in large-scale train-track monitoring, which is meaningful for the safe operation of rail transport.

Wavelength-Division Multiplexing Fiber Bragg Grating Vibration Sensing Demodulation System

2013 ◽  
Vol 718-720 ◽  
pp. 636-640
Author(s):  
Fang Dong Zhu ◽  
Dong Sheng Zhang ◽  
Yong Xing Guo ◽  
Li Tong Li
Keyword(s):  
Fiber Laser ◽  
Fiber Bragg Grating ◽  
Wavelength Division Multiplexing ◽  
Tunable Filter ◽  
Vibration Measurement ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Wavelength Division ◽  
Vibration Sensors ◽  
Vibration Sensing

A fiber Bragg grating (FBG) sensing network for vibration measurement is proposed and demonstrated in this paper. The light source of the described sensing technique is an erbium-doped fiber laser applying a 980-nm laser diode and a fiber Fabry-Perot tunable filter. The fiber laser has a 40nm tuning range, allowing many vibration sensors to be multiplexed on the same fiber. Reflected light wavelength shift of the FBG sensor caused by strain variation is converted to intensity deviation, which avoids a complex demodulation process. This sensing scheme can effectively increase the demodulation speed of sensing system up to 20 KHz. At least 20 FBGs can be multiplexed alone a fiber.

scholarly journals MR compatible force sensing system for real-time monitoring of wrist moments during fMRI testing

2006 ◽  
Vol 155 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Joseph Hidler ◽  
Timea Hodics ◽  
Benjamin Xu ◽  
Bruce Dobkin ◽  
Leonardo G Cohen
Keyword(s):  
Real Time ◽  
Force Sensing ◽  
Real Time Monitoring ◽  
Sensing System

A High-Throughput Impedance Sensing System for 3D Cell Drug Permeability Gradient Effect Real-Time Monitoring

2020 ◽  
Vol MA2020-01 (27) ◽  
pp. 1900-1900
Author(s):  
Yong Qiu ◽  
Yuxiang Pan ◽  
Chenlei Gu ◽  
Deming Jiang ◽  
Xing Liu ◽  
...  
Keyword(s):  
Real Time ◽  
High Throughput ◽  
Real Time Monitoring ◽  
Impedance Sensing ◽  
Drug Permeability ◽  
Gradient Effect ◽  
Sensing System
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